Radio signaling system



March 30 1926. I 7

- a. H. CLARK mm smmuue svs'rml Filed April 26, 1921 GEO/Y6K H. (MK

95 his filth/ma an audible irate atuthe transmitting station" I so.

Patented Manlint 1926;

"ALA EU ,qnonen n. CLARK, on BROOKLYN, NEW YORK, Assienon ri o nii'nio 'oonronacrro ior vmnrcaga conroaa'rion onnnL wnnn w I .nanro SIGNALiNG s s'r'n 'Application fiia A riiae, 1921. serial No. 464,555:

To all 'whom it may concern."

iBe it known that I, GEORGE CLARK, a

I citizen of the United States and a resident of Brooklyn, Newi'ork, have invented certain new and useful Improvements in Radio Signaling Eysteins, -of which the following .is 'a specification accompanied by; drawings.

The present invention relates to improve- .ments in radio signaling with continuous waves. As isnvell :known, high frequency continuous waves or oscillations are incapable of audible reception Without special meansutilized either atithetransinission stationIoriatithereceiving station. I

-In case that the Waves are modulated at no special means are necessary at the recelving station for I detection and any receimng setequipped for detection of damped Waves Will detect :the modulated continuous Wayes. In modulating the Wave at the transmission station it is usual to super in pose .an' E. M. of I low frequency on the main E. M. :F. .inkthe antenna or to change the constants .inthe antenna at an'au dible rate in orderltoproduce the modulation.

Instead I of :thus changing [the constants of the antenna or adding currents from another source 1 periodically absorb at an audible rate portions :of the signal Waves so that the" same do not. get in the antenna. Thus the signal current ;is in effect Ain'terruptedat an audible rate .by the absorption in a nonv t with modulating OI' PGHOClICELllY absorbing means sends theloscillations alternately into I theabsoi'ption circuit.

In ny previous application I have specifically described an arrangement embodying an absorption circuit comprising inductance; ca ac ty and resistancefl To j divert the os cilat ons train the antenna to the QbSOiP,"

tion circuit the resistance is short cireuited In accord and 'i iethods which I have discovered for diverti-ng the osc llations to either the antenna or whichdoes not substantially ing of the absorption circuit. I

I have found thatIthe oscillations may "al s beidivei'ted to either the antenna or the ab-. sorption circuit byslight changes in the tuning of the absorption Icireuit, Witho-ut affect the tun I necessarily substantially I altering the re sistance. I have also found that-the absorption circuit functions much better wheny adjusted to a Wave length much-shorter than the (main wave length. dVhen the vconstants are adjusted to a Wave lengthofabout one-Q third the main wave length a slight -Varia- :1

tion of the inductance or capacity is Suf licient to divert the oscillations "iroin-the'absorption circuitto the antennaor Vice -versa; These discoveries are (utilized in thepresent invention in a manner which Will forth more fullyherea fter. I I I While my iiiventionqis "applicable ,';to various types of high ifrequeneycontinuous' wvave has thernoneradia' ting absorption c-ireuit ifor producing'the .signal g In the embodiments .o-fitheii iyentionrhereindescribedthecurrentp is periodically absorbed in ithevzabsorption; g

be-set I generating systems, it is tleSQlilDGtlTili connection 'Wlth an i are converter system which eillations into either the absorption circuit or the antenna'when the ikeylis open and in" the closed positionyworking' 1n con]unct1on audible. irate. I p One object of my invention isitodive-r-tthe the antenna ,aiidoscillation circuit at an oscillations .from the antenna to the absorp tion circuit or. i i ce .vei'saby yai'yi g the ftun ingot the absorption'cii'cui Auotheriobject of my invention isto di vert the oscillations 'at an audible rate du-r 'ing signaling :to produce signals whichqcan r bexreceived Without special means. I I

Further objects of the'lnvention w ll ap peiuliii the following clescription otseveral enibodiin'nts 'ott 'in'y nVention wh ch are of an arrangement embodying the invention as applied to an arc converter in which signaling and modulation are both produced by .varying the tuning of the absorption circuit.

Figs. tationsof modifications.

In the drawings, 1 is an are fed by a generator 2 and having'a field coil 3 to provide theffield for influencing the are in the well known way. 7 The antenna a is connected to the upper electrode through the adjustable loading coil 5 and the lower electrode is connected to theground at 65111 Fig. 1. the absorption circuit comprises capacity 7 and inductance, the latter coinprising coil 8 with adjustable Contact andan' additional inductance 9 of small .value adapted to be readily 'cut into or out of the absorption circuit "ina manner which will be; further described. In the .modification of Fig. 1 the absorption circuit contains no g special resistance vand the signaling as well asthe modulation is produced bydetuning.

For nodtdationa contact arm '10 is moved back and .forth on the turn 9 of inductance to cutthis-in and out of the circuit at a rate, corresponding to an audible note.

therefore remain constant during "this period. A; signaling j-key' 14 is connected "across the inductance9 soith'at in the raised; position it short circuits the-inductance 9v and when depressed fortelegraph signaling. it opens the. short circuit: around the induc- 'There' are, of course, many ways of doing this mechanically, but in the drawing I have shown a-cam-ll rotated by a. motor 12,which.

acts on apivoted lever 13, which is integral with-contact arm 10. Thecam is preferably "shaped so that no'moveinent ofthe contact arin is produced'during a considerable portioii of each revolution and the tuning will tance." l

VVith the arrangement described all of the oscillations will be sent into either'th'e ab- SOIPUOHCIICUH] or the antenna astdesired I fwhen the; telegraph key is up; This will depend upon whether the absorbingicondition of the absorption circuit is adjustedto occur when inductance '9 is in circuit or when the latter is short circuited. ing maybe eliected n either condit on.

V Howevenif we consider the circuit to be non-absorbing when the inductance 9 is short circuited, the operation will be as follows: VVhenthe key 14 is up and no sig nals arebeing sent, theoscillations favor the antenna to the practical exclusion of the absorbiiigcircuit and the former will thus radiate I wh ch however cannot be detected without special means at the receiving station. This condition will eXlSt regardless ofthe opers 'ation ofthecontactarm which operates 111, conjunction with the inductance 9 and 2 and3 are diagrammatic represencontinuous unmodulated Q waves during such periods the operation of the modulating mechanism described has no effect on the character of the radiation. When the key is operated to produce tele-Iv graphic signalsythe short circuit on the inductancei) .is removed-during the signaling interval and the oscillations will be diverted alternately to the absorption circuit and the antenna in accordance with the position oi;

. the contact arm, When the point 15 of the cam is in contact with the lever 13, the iii- I ductanc-e 9 is cutinto the absorbing circuit and substantially all of the oscillations are diverted frointhe antenna circuit. When the cam rotates 180 so that point- 16 is in contact with thelever the inductance 9-i5 short circuited by the contact arin 1O, thus disturbing the absorbin conditionfof: the.

absorption circuit and' causing ther oscilla tions to return to the antenna circuit! Thisalternation of the oscillations between "the two 0110111138' occurs attonefrequency; and

the resulting groups of oscillationsmimpressed on the antenna during .the period when the key is operated which correspond tO'TlOtS and dashes will occur. in. groups of oscillations having .an' audible group. frequency which can be detected 'witliout'using any special means at the receiving station: Obviouslythe tuning can be varied and cuit in the same manner. as "heretofore described. Y

. In either case inaccordance with the e mbodime'nt described modulation'is produced by] changing the tuning of the absorption circuit at an audiblera-te andJsignaling is also produced by changing the tuning.

Figs. 2 and 3 radiation ofthe samel'char acter as described in connection with Fig.- 1 issecured, but signaling is done without havingvthe movements of the key-affect the tuning of theabsorption circuit. Fig. 2 shows an arrangement in which the absorbing circuit is detuned by varying signaling produced inthe same way as at.

Y In accordance with the modifications of the capacity. A'condenser 17 of small value comprising the plate 18 rotated by asinotor at an audible rate is utilized to 'detun-ethe absorption circuit and alternately send the oscillations into the antenna and absorbing? circuit to giv'etone characteristics; Such an arrangement isillustrative of the use ol'ai condenser. insteadof-the inductance 9 of; Fig. 1101 detuninglthe absorption circuit.- It is to produce detuningfl The periodically Va antenna sometimes c'ona'eirientito utilize a resist-ance;,

in al l y in circuit and gcontinuous uuiIn'oclu.-; lated Oscillations are impressed'f'ionithelanten-11a circuit exce t during: signaling when this; is short 'circuited. byZ-'lre 1A andii'the oscillations are thenl periodically absorbed; by the absorption circuit .at an audible rate-- due to theperiodical detuning of the absorption circuit by therotat-ing condenser.

Fig. 3 shows an arrangement in which the resistance 18 is short circuited' for signaling by means of the telegraph key asin Fig-2 and the inductance is varied asjin Fig, I

riable inductance comprises a, pair of flat coils 20, 21 and'a' conducting shield 22 movable into and out of the space' between'the coils to vary the inductance. "The'periodlc movement of the shield through the field between the coils at an audible rate is secured by means of a.'rotating cam 23 acting on a lever 24 for example, In each ofthe modifications described it will be understood that the absorbing circuit constants are preferably such thatrthe tuning corresponds toa wave length considerably less, and usually about one-thlrd the main wave length, as have found'that the osclllations may be more readily diverted by mistun-ing than when the absorbing'circult is adjusted to the main wave length Having described myinvention, what. I

claim is: p n I 1. The method of signalingwhich comprises 1 generating high frequency oscillav tions, supplying the energy thereof alternately to two tuned circuits, radiating signal waves from one thereof, absorbing energy in the other thereof, and controlling the alternation therebetween by mechanical varlation of the impedance elements at'an audio rate. I

2. The method of signaling which comprises generating high frequency oscilla-I tions, feeding said oscillations alternately onethereof, absorbing energy in the other' thereof, and controlling a the alternation therebetween byimoving a'portion of the impedance elements in the absorbing circuit;

at an audible rate, and by shunting impedance elements in the same circuit at a signal 7 code rate.

This'is shown: in Figs; i 2' and In Fig.2theiresrstance l9 l'S'llOI' iing, high frequency: electricalloscillations,tan antenna cirrcl'ui v V absorbing; ci r cuit also connected thereto i' npedancexamcans; included in said absorbing circuit and; power I actuated;meansrfor; inov; in giportiornsith ereof aa tan audible frequency rate whereby the. impedance thereofis varied and the oscillations caused to galternateibe tween said antennaand said circuit.

I A 'radi'o signalingsystemjcomprisingla 241 source of energy, a converterffor producing tenna circuit connected thereto, a tuned ab? portions thereof at audible; frequency rate, wherebyjthe impedance thereof is varied: and, the oscillations "caused to altercircuit to shunt an impedance whereby fsaid alternation is suspended duringnon-signal j ingvperiods; I a

6. In a radio signaling system, the'combination of an antenna,a generator of continuous oscillations, an absorption circuit, a resistance in said circuit adaptedjtoi damp signaling means adapted .to I intermittently for said absorption,circuit,' and means-for periodicallychanging the effective Values of the constants;of'saidtuning means at anaudible-rate. 7 In a' radio signalingsystem, the com; bination of an antenna, a generator of continuous oscillations, an absorption, circuit, a

onnected" thereto, aa tuned high frequency electrical oscillations, an anon" sorbing'circuit also connected 'thereto, iIn-' pedance means included 111 said absorbing i c1rcu1t, .power actuated i'me'ansfor moving I oscillations out of the absorptioncircuit,

1 aA' radio signalingsysteml;comprising' V I 2 euros ofenergmla iconverter-sforqtiroduce 1 nate between said antenna andsaid circuit, and a keying-means cooperating withf'said' short circuit said resistance, tuning means resistance in said circuit: adapted to damposcillations out ofythe, absorption'circuit,

signaling means adapted to intermittently "short circuit said resistance, an inductance for tuning said absorption circuit, and means for periodically changing the effective tun-' ing inductance at an audible rate. I

' 8. In radio signaling systems, the combination of an antenna, an arc generator of continuous oscillations for energizing said antenna, an absorpt-ion circuit bridged across. said are generator for absorbing os- 'cillations produced thereby, said absorption circuit having its constants so chosen as to have a predetermined resonance characteristic and to be resonant at a" wave length substantially less than the wave length of the oscillations radiated, and means fo r'pe-' riodically varying one of the constants of said absorbing circuit between predetermined fixedvalues at an audible rate to periodical ly modify said resonance characteristic whereby a characteristic tone is impressed I on the radiated oscillations. i a 9. In radio isignalingsystemgthe combi- 

